The present invention relates generally to drive belts for track-type machinery and, more particularly, to a protective cover for guide blocks on a drive belt.
Agricultural and construction machines often operate in soils such as mud and sand where it is difficult for conventional wheel type machines to gain traction. Therefore, alternate types of machines capable of operating in such adverse soil conditions are in demand.
One type of such machine is one having an undercarriage incorporating a track assembly as shown in FIG. 1 including a driving sprocket wheel 10, an idler wheel 12, a drive belt 14 which extends around the driving sprocket wheel 10 and the idler wheel 12, and a plurality of roller wheels 16 arranged in contact with the inner surface 18 of a ground contact region of the drive belt 14 between the driving sprocket wheel 10 and the idler wheel 12. A conventional drive belt 14 has a plurality of rubber lugs 20 formed on its outer circumference 22, and a plurality of protruding guide blocks 24 formed on the inner surface 18 to protrude at a central region thereof and spaced to each other by a predetermined distance in the longitudinal direction of the drive belt 14. The guide blocks 24 are engaged by a plurality of driving members 26 such as drive pins, teeth, or the like disposed between the wheel portions and adapted to drive the drive belt 14.
To accommodate the guide blocks 24, each of the wheels 10, 12, 16 includes an inner wheel portion 28 and an outer wheel portion 30 spaced from each other on an axle 32 at a distance at least the width of the guide blocks 24. The inner wheel portion 28 and the outer wheel portion 30 also help keep the drive belt 14 in alignment with driving sprocket wheel 10.
A plurality of guide rollers 60 guide and support the belt 58 between the drive and idler wheels 50,54 as shown in FIG. 7. The tensioning means 62 tensions the elastomeric drive belt 58 between the drive wheel 50 and the idler wheel 54.
As in the positive drive system, the guide blocks 64 in the friction drive system undergo wear and tear, requiring the replacement of the entire belt 58 even if only a few of the guide blocks 64 on the belt 58 are damaged. Thus, as in the positive drive system, it is desirable to provide means for protecting components subject to heavy wear and tear, thereby increasing the life of the belt 58.
Another type of such machine which may utilize the protective cover is a friction drive system as is shown in FIG. 7. A belted work machine 46 includes a drive wheel 50, an idler wheel 54, and endless belt which extends around the drive wheel 50 and idler wheel 54. The plurality of the guide blocks 64 are spaced to each other by a predetermined distance. The guide blocks 64 are received by guide channels 66.
During operation, continuous frictional contact between the guide blocks, the driving members, and the idler wheel can cause damage to the guide blocks. Further, when the machine maneuvers over sloped surfaces, the forces on the guide blocks increase due to the fact that the guide blocks support the forces required to drive the machine over the terrain, along with force components of the machine""s weight. The increased forces cause greater wear and tear on the guide blocks, requiring replacement of the entire drive belt even if only a few of the guide blocks on the drive belt are damaged. It is desirable to provide means for protecting components subject to heavy wear and tear, thereby increasing the effective life of the drive belt.
Referring to FIG. 8, the configuration of the preferred drive wheel structure 68 and the endless belt 58 are shown. The guide block 64 is received by the guide channel 66.
Currently, there are devices requiring additional structure on the track assembly to improve the alignment of the guide blocks with the idler wheels. Purcell et al. U.S. Pat. No. 5,433,515 discloses guide rollers for a flexible drive belt including first and second rotatable guide rollers adapted to contact guide blocks on the drive belt and guide them into the space between the inner and outer wheel portions of the idler wheel 10. The Purcell et al. device prolongs the useful life of the flexible guide blocks by guiding them into the opening between spaced idler wheels, thereby lessening frictional contact and damage between the idler wheel and the guide blocks. The Purcell et al. device does not, however, disclose means for a covering the guide block to help protect it from wear.
Accordingly, the present invention is directed to overcoming one or more of the problems as set forth above.
In one embodiment of the present invention, a protective cover member for a guide block on a drive belt includes an inner portion shaped to substantially conform to at least a portion of the outer surface of the guide block. The cover member is attached to the guide block using suitable attachment means such as bonding the cover member to the guide block, mechanical fasteners such as screws or bolts, and/or using an interference design whereby the cover member is retained by frictional forces or by snapping around a portion of the guide block. The outer surface of the cover member is shaped and sized to be engaged by drive members associated with a sprocket drive wheel. The cover member may be constructed of material that is capable of withstanding higher temperatures and forces compared to the material of the guide blocks.